Components  

Low-impact development (LID) concepts help retain the hydrologic characteristics of each site, improve stormwater quality, maintain downstream stability, and reduce the need for conventional stormwater management and conveyance systems.
  
   
These concepts must be integrated into the site planning process to achieve sustainable solutions. The fundamental concepts include: using hydrology as the integrating framework, using conservation strategies, thinking micromanagement, controlling stormwater and erosion at the source, using simple, nonstructural methods, creating multifunctional landscapes, and utilizing integrated management practices (IMPs).  
   

Using hydrology as the integrating framework refers to utilizing various planning tools (including hydrologic analysis) and control practices to preserve the natural hydrologic functions of the site.

  
   

LID uses conservation and minimization to reduce the footprint of development and the disturbance of natural systems during landscape development.

 
   

Controlling stormwater and erosion at the source is a key element in restoring the predevelopment hydrologic functions. The goal is first to minimize and then mitigate the hydrologic impacts of land use activities closer to the source of generation. Natural hydrologic functions such as interception, depression storage, and infiltration should be evenly distributed throughout a site. This is referred to as a distributed, at-source control strategy and is accomplished using micromanagement techniques throughout the site.

 
   

With LID, every urban landscape or infrastructure feature (roof, streets, parking, sidewalks, and green space) can be designed to be multifunctional, incorporating detention, retention, filtration, or runoff use.

 
     
  For details about specific LID technologies see the “Construction and Siting Issues” section.